Fluid flow indicator for arc plasma device



June 1965 R. AJHAWKINS ETAL 3,191,083

FLUID FLOW INDICATOR FOR ARC PLASMA DEVICE Filed Aug. 2, 1961 FLUID SUPPLY MEANS l8 CONTROL CONSOLE II V ROBERTA. HAWKINS GERALD A. JENSEN INVENTORS BY 10, W

4 v ORNEYS United States Patent 3,191,088 FLUID FLOW INDICATOR FOR ARC PLASMA DEVICE Robert A. Hawkins, Topsfield, and Gerald A. Jensen,

Lowell, Mass., assignors to Avco Corporation, Cincinnati, Ohio, a corporation of Delaware Filed Aug. 2, 1961, Ser. No. 128,817 5 Claims. (Cl. 313-231) This invention relates generally to a fluid flow indicator for an arc plasma device, and in particular to an audible device which indicates that an adequate supply of working fluid is flowing in the arc plasma device.

Typically, an arc plasma device uses a working fluid, usually an inert gas. Arc electrodes are usually immersed in the working fluid and when an arc is struck, the arc flows through the working fluid.

A common arc plasma system comprises a fluid supply means, a control console, and fluid conduits connecting the fluid control console to an arc plasma device.

The fluid from the fluid supply means flows through the control console where it passes through conventional metering and control equipment. From the control console the fluid passes through the conduit, which may be several feet in length, to an arc plasma device.

Generally, the control console contains a device for preventing an are from being struck if the quantity or pressure of the working fluid being supplied to the console is inadequate. However, the control console is generally incapable of providing protection in the event of a gas leak in the conduit or the arc plasma device. In short, the control console has no control over the working fluid after the working fluid leaves the console.

It is an object of the invention to provide a fluid flow indicator for an arc plasma device which indicates the presence of an adequate flow of fluid in the arc plasma device.

It is another object of the invention to provide an audible fluid flow indicator for an arc plasma device.

It is another object of the invention to provide an audible fluid flow indicator for an arc plasma device, which indicator is activated and operated by the working fluid.

It is still another object of the invention to provide an audible fluid flow indicator comprising a cavity activated by the flow of working fluid to generate an audible signal.

In accordance with the invention, a fluid flow indicator for an arc plasma device having electrodes across which an arc is struck comprises means for supplying a working fluid to the electrodes. An audible device, preferably a cavity having an audible resonant frequency, is also provided. The cavity is in fluid communication with the working gas and activated, i.e., caused to resonate, thereby. The audible device-the cavityemits an audible signal when there is an adequate amount of working fluid being supplied to the arc plasma device.

The novel features that are considered characteristic of the invention are set forth in the appended claims; the invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in conjunction with the accompanying drawings, in which:

FIGURE 1 is a schematic representation of an arc plasma device including a fluid flow indicator embodying provisions of the present invention.

FIGURE 2 is a cross sectional detail, taken along line 22 of FIGURE 1, of one form of an audible device.

Referring to FIGURE 1 :of the drawings, there is shown, schematically, an arc plasma device which includes a pair of electrodes 11 and 12. Electrode 11 is a nozzle electrode and includes a central passage 13. In-

serted partially within the passage 13 and concentric therewith is the second electrode, which will be referred to hereinafter as the center electrode 12.

As seen in FIGURE 1, the center electrode 12 passes through a fluid chamber 14. Fluid chamber 14 is preferably made from a non-electrical conducting material, a plastic for example. The fluid chamber 14 includes an input aperture 16, and an output aperature 15, the latter opening into the central passage 13.

A working fluid is supplied to the chamber 14 from a fluid supply means 17 through a control console 18. From the control console 18, the fluid flows through a conduit 19 to a fluid flow indicator assembly 21 which is secured to the walls of the fluid chamber 14. See FIG- URE 2. As will become obvious hereinafter, the fluid flow indicator assembly 21 is in fluid communication with the conduit 19 and the aperture 16.

Referring to FIGURE 2 of the drawings, there is depicted a fluid flow indicator assembly 21 which includes the audible device 20 and a conduit 25.

The audible device 20 comprises substantially a cylindrical wall 22 and a cap 28 defining a closed resonant cavity 23. The lower end of the cavity includes the aperture 16 into the fluid chamber 14 and an edge 27.

As seen in FIGURE 2, the conduit 19 is coupled to the conduit 25 by a connector means 26 which, for the purpose of illustration, is a threaded coupling. There is included in conduit 25 a baffle 24 for directing the flow of working fluid to the aperture 16.

Conduit 25, aperture 16, fluid chamber 14, and aperture 15 comprise means for supplying a working fluid to the electrodes 11 and 12.

Manifestly, the audible device 21 functions in the same way as a closed organ pipe. A column of working fluid, in the cavity 23, is set into vibration (resonated) by the flow of working fluid over the edge 27. The resonant frequency is determined by the dimensions of the cavity. It has been determined that a cavity two and one-half inches long resonates at approximately 3,000 cycles and provides an audible signal which can be distinguished from the noises generated by the arc plasma device when it is in operation.

It will be noted that the audible device 21 is located in the immediate vicinity of the electrodes where the arc is struck. When activated it provides a continuous and reliable indication that the arc plasma device is receiving an adequate fluid supply.

It is within the contemplation of this invention that the audible device not be solely limited to a resonant cavity. A vibrating reed or tuning fork may be used to generate an audible signal.

The various features and advantages of the invention are thought to be clear from the foregoing description. Various other features and advantages not specifically enumerated will undoubtedly occur to those versed in the art, as likewise will many variations and modifications of the preferred embodiment illustrated, all of which may be achieved without departing from the spirit and scope of the invention as defined by the following claims.

We claim:

1. In an arc plasma means having electrodes across which an arc is struck, and means for supplying a working fluid to said electrodes, a fluid flow indicator comprising an audible means disposed in said are plasma means in fluid communication with said working fluid supply means and activated by the working fluid for emitting an audible sound when an adequate supply of fluid is being supplied to the arc plasma means.

2. A fluid flow indicator as described in claim 1 in which said means for emitting an audible sound comprises a resonant cavity coupled to said working fluid supply means and which emits an audible signal when resonated by said working fluid.

3. A fluid flow indicator as described in claim 2 in which said resonant cavity requires a minimum fluid pressure to operate.

4. An arc plasma means comprising: a nozzle electrode including a central passage; a second electrode spaced from said nozzle electrode; a chamber including working fluid outlet means in communication with said central passage and working fluid inlet means; conduit means for coupling said chamber to a fluid supply means; and a fluid flow indicator disposed between the inlet means and conduit means including a second fluid outlet means and second fluid inlet means in fluid communication with said inlet means and conduit means respectively 15 '4 for emitting an audible signal when an adequate supply of working fluid is being supplied to the arc plasma device. 5. An arc plasma means as described in claim 4 in which said fluid flow indicator is a resonant cavity.

References Cited by the Examiner UNITED STATES PATENTS 2,483,657 10/49 Messick.

2,794,341 6/57 Vonnegut 73-194 10 2,941,063 6/60 Ducati et al.

2,995,035 8/61 Bloxsom et al. 313-231 DAVID J. GALVIN, Primary Examiner.

BENNETT G. MILLER, JAMES D. KALLAM,

Examiners. 

1. IN AN ARC PLASMA MEANS HAVING ELECTRODES ACROSS WHICH AN ARC IS STRUCK, AND MEANS FOR SUPPLYING A WORKING FLUID TO SAID ELECTRODES, A FLUID FLOW INDICATOR COMPRISING AN AUDIBLE MEANS DISPOSED IN SAID ARC PLASMA MEANS IN FLUID COMMUNICATION WITH SAID WORKING FLUID SUPPLY MEANS AND ACTIVATED BY THE WORKING FLUID FOR EMITTING AN AUDIBLE SOUND WHEN AN ADEQUATE SUPPLY OF FLUID IS BEING SUPPLIED TO THE ARC PLASMA MEANS. 